[99.03] Dusty Nuclear Disks in Early Type Galaxies

We present early results from a WFPC2 survey of early type
galaxies aimed at searching for small (r ~ few hundred
pc) nuclear dusty disks. In order to examine the influence
of the host environment on the detection of such disks, two
volume-limited samples are studied. One examines an
IRAS-selected archival sample of all early-type galaxies
at v < 3000 km/s with 3\sigma or greater detection at
100\mum, and the other surveys, in WFPC2 snapshot mode, a
large selection of early-type galaxies with v < 3400 km/s,
and b > 20\deg~regardless of IRAS properties. Our
analysis shows that 16% of the 67 non-IRAS selected
galaxies harbour nuclear dusty disks, while 38% of the 42
IRAS selected galaxies do.

We discuss the role played by galaxy environment in
determining the frequency of dusty disk, and investigate the
connection between the presence and morphology of the disks
and the type and level of nuclear activity. The galaxies
found to harbor nuclear disks in our survey will make up an
important database for future studies aiming at deriving the
central black hole masses, through the use of gas dynamics,
and examining their demography.